Lift Question

I was reading thru the JCWhitney Catalog and found a 3" suspension lift that will fit my 90 XJ for $100 and I'm not sure but I think it's a Rough Country. For that price/brand is that a good deal? I'm not sure if it uses lift blocks for the rear axle but I've heard to stay away from the lift blocks, why is this? When installed will I need to modify any steering or braking components?
Thanks

For that price I'm sure it comes with lift blocks. The bad thing about blocks is that it give the axle more leverage against the springs. This can lead to wheel hop, and twisted up springs. You need to see what all is included in the kit. You will need new control arms to adjust caster, and it would be a good idea to get an adjustable trackbar as well. Also anytime you lift a vehicle, some steering adjustments need to be made. Mainly a Frontend Alignment.